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Subject: Re: Verified Null-Move Pruning, ICGA 25(3)

Author: Frank Phillips

Date: 12:36:31 11/27/02

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On November 27, 2002 at 15:15:50, Robert Hyatt wrote:

>On November 27, 2002 at 13:48:50, Frank Phillips wrote:
>
>>On November 26, 2002 at 20:02:06, Robert Hyatt wrote:
>>
>>>On November 26, 2002 at 16:21:00, Omid David Tabibi wrote:
>>>
>>>>On November 26, 2002 at 15:58:06, Gian-Carlo Pascutto wrote:
>>>>
>>>>>On November 26, 2002 at 15:55:56, Omid David Tabibi wrote:
>>>>>
>>>>>>So it is reasonable that on every program starting from a certain depth >adaptive null-move pruning will always construct a smaller search tree.
>>>>>
>>>>>Don't you mean the other way around?
>>>>>
>>>>
>>>>Yes :-)
>>>>
>>>>Starting from a certain depth, verified null-move pruning will always construct
>>>>a smaller search tree than the adaptive one.
>>>>
>>>>
>>>>
>>>>>--
>>>>>GCP
>>>
>>>
>>> I am doing some testing now.  First thing I noticed is that for WAC, the
>>>time-squared
>>>measurement went down very significantly for your algorithm.  And I have not
>>>modified
>>>anything such as turning null-move off when low material happens, since your
>>>idea will
>>>catch the zug problems.
>>
>>Have you tried Fine70?
>>
>>Frank
>
>Yes...  and I told Omid that this is a strange case as if I allow null-move in
>pawn-only
>endings, which turns it on for fine 70 of course, things get wrecked inside the
>search
>somehow.  A 45 ply search fails to see that Kb1 wins where normally an 18-19 ply
>search is enough...
>
>
>>>
>>>


Snap... and I have no idea why.  I thought it was my implementation of a similar
 idea (from Bruce's site) of verification search, but I copied the scheme in
Omids paper and it does the same.

Frank



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